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吴诗晓, 陆春松, 朱磊, 等. 2021. 从夹卷的角度探讨雾不同阶段微物理量的变化机理[J]. 大气科学, 45(5): 1057−1070. doi: 10.3878/j.issn.1006-9895.2102.20189
引用本文: 吴诗晓, 陆春松, 朱磊, 等. 2021. 从夹卷的角度探讨雾不同阶段微物理量的变化机理[J]. 大气科学, 45(5): 1057−1070. doi: 10.3878/j.issn.1006-9895.2102.20189
WU Shixiao, LU Chunsong, ZHU Lei, et al. 2021. Examination of Mechanisms Underlying the Variations of Microphysical Properties in Different Fog Phases from the Perspective of Entrainment [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 45(5): 1057−1070. doi: 10.3878/j.issn.1006-9895.2102.20189
Citation: WU Shixiao, LU Chunsong, ZHU Lei, et al. 2021. Examination of Mechanisms Underlying the Variations of Microphysical Properties in Different Fog Phases from the Perspective of Entrainment [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 45(5): 1057−1070. doi: 10.3878/j.issn.1006-9895.2102.20189

从夹卷的角度探讨雾不同阶段微物理量的变化机理

Examination of Mechanisms Underlying the Variations of Microphysical Properties in Different Fog Phases from the Perspective of Entrainment

  • 摘要: 夹卷混合过程作为影响云雾的主要物理过程之一,对云雾的生命周期、云雾降水的形成过程、辐射传输过程和气溶胶间接效应等都有着重要影响。本文从微物理和动力两个方面探讨辐射雾中的夹卷混合机制,既促进对夹卷混合机制的理论认识,又从新的角度来讨论辐射雾的发展消亡过程。利用2006年和2007年冬季在南京进行的雾综合观测的资料,研究了9个个例中的夹卷混合机制。首先,针对2007年12月10~11日这一次辐射雾过程进行详细分析,探讨了不同阶段微物理量的变化和夹卷混合机制。结果表明:成熟阶段主要为极端非均匀夹卷混合机制,数浓度和含水量同时减小,体积平均半径却基本保持不变;快速消散阶段主要为均匀夹卷混合机制,各微物理量同时减小,互为正相关关系。除了微物理,本文也分析了夹卷混合机制的动力特征,计算了过渡尺度数,发现在成熟(快速消散)阶段,过渡尺度数小(大),有利于极端非均匀(均匀)夹卷混合机制的发生。其次,分析了其他8个个例中微物理量之间的相关关系,发现体积平均半径和含水量之间主要呈正相关关系,以均匀夹卷混合为主。所得结果有助于夹卷混合机制参数化方案的开发,同时为辐射雾的模拟预报提供参考。

     

    Abstract: As one of the main processes affecting cloud and fog, the entrainment-mixing process has an important impact on the cloud/fog life cycle, precipitation formation, radiative transfer, aerosol indirect effect evaluation, and so on. This study discussed the entrainment-mixing mechanisms in a radiation fog from the microphysical and dynamical perspectives, which not only improved the theoretical understanding of entrainment-mixing mechanisms but also revealed the development and dissipation of radiation fog from a new perspective. Using the comprehensive field observational data in Nanjing during the 2006 and 2007 winter, entrainment-mixing mechanisms in nine fog cases were analyzed. First, a radiation fog event during December 10–11, 2007, was studied to understand the microphysical relationships and entrainment-mixing mechanisms during different phases in detail. Results showed that the extreme inhomogeneous entrainment-mixing was found in the mature phase, in which the volume-mean radius slightly changed as the number concentration and liquid water content decreased. The homogeneous entrainment-mixing was found in the rapid dissipation phase, in which all microphysical properties decreased simultaneously with positive correlations. Except for microphysical properties, the scale number was calculated as a dynamical measure for entrainment-mixing mechanisms. In the mature (rapid dissipation) phase, the scale number was small (large), indicating that the extreme inhomogeneous (homogeneous) entrainment-mixing was most likely to occur. The microphysical relationships of the other eight fog events were then examined, which indicated that the volume-mean radius had positive correlations with the liquid water content in general, i.e., homogeneous entrainment-mixing dominated. The research results were helpful to the development of parameterization schemes of entrainment-mixing mechanisms and provided a reference for the simulation and prediction of radiation fog.

     

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